Orbital sanding tool

Abstract

The orbital sander of the present invention eliminates many of the disadvantages of the prior art sanders by providing a compact, lightweight, and economical sander having a body and shroud formed from an injection-molded synthetic polymeric material. The head is replaced using a built-in plunger which engages notches in the spindle, without the need for tools. The built-in plunger enables the flexible shroud of the prior art to be replaced with a rigid polymeric shroud positioned with a minimal gap between the shroud and the head or shoe. The polymeric shroud is attached to the rest of the polymeric body structure by three screws and two pins. The pins project upwardly from the polymeric shroud and into precise engagement with the polymeric body structure, thus reducing the required drilling and tapping, providing rotational stability, and increasing the strength of the connection between the two parts. The air control valve is securely held in the housing using a set screw having a dog which engages a groove in the air control valve to resist the axial force tending to eject the air control valve from the body structure. Finally, a new muffler is used which creates a circuitous path for the exiting air, and thus dampens its acoustic energy.

What is claimed is:  
     
       1. An orbital abrading or polishing tool, comprising: 
       a tool body to be held and manipulated by a user;  
       a motor carried by said body;  
       an orbital drive structure driven rotatably about a first axis by said motor;  
       a spindle having at least one notch along its outer circumference and which is connected to said orbital drive structure for rotation relative thereto about a second axis offset from said first axis to drive said spindle in an orbital path about said first axis as said orbital drive structure turns;  
       a head threadedly connected to said spindle and adapted to carry an element for abrading or polishing a work surface; and  
       a plunger passing through said body and movable radially inwardly, said plunger movable between a first position and a second position, wherein in said first position said plunger does not contact the outer circumference of said spindle and in said second position said plunger engages said at least one notch for any position of said spindle along said orbital path.  
     
     
       2. The tool of  claim 1 , wherein: 
       said motor is driven by pressurized air.  
     
     
       3. The tool of  claim 1 , further comprising: 
       an element carried by said head for abrading or polishing a work surface, wherein said element is sandpaper.  
     
     
       4. A method for replacing a head of an orbital abrading or polishing tool, comprising: 
       (a) pressing on a plunger to contact a spindle;  
       (b) manually rotating a first head threadedly connected to said spindle until said plunger enters a notch along the outer circumference of said spindle to lock said spindle against rotation;  
       (c) manually rotating said first head while said spindle is locked against rotation so that said threaded connection is broken;  
       (d) positioning a second head relative to said spindle so that said second head can be rotated relative to said spindle to form a threaded connection therebetween;  
       (e) manually rotating said second head to threadedly and tightly connect said second head with said spindle;  
       (f) releasing said plunger to disengage said plunger from said notch and thereby allow said second head and said spindle to freely rotate.